Field of the Art
The disclosure relates to the field of fishing equipment, and more particularly to the field of maintaining the health of live fish in a captive, mobile environment.
Discussion of the State of the Art
The sport of fishing involves a number of technologies designed to keep fish healthy until needed. In most cases, the equipment utilized for live bait is often the same equipment utilized for the holding of caught fish though the actual containment areas will be separated from one another.
The technology in use today for preserving the health of fish while fishing commonly involves the use of a tank or live well of some sort through which water is re-circulated, the temperature is modulated as necessary and oxygenation of the water occurs through the introduction of fresh water or aeration of the tank water. All three of these things (water temperature, oxygenation and water cleanliness), work together to help keep the contained fish healthy.
Re-circulation of water through the live well helps to maintain the proper level of oxygen. Water being returned to the live well via the re-circulation pump is gently sprayed into the tank thus allowing the returning water to absorb oxygen prior to landing in the live well. This re-circulation process also brings about the need for temperature modulation.
Water in any kind of live well will change temperature through simple absorption of the heat or cold in the environment. Aeration of the re-circulated water being returned to the live well will lower the temperature of the water. The ideal design of a live well is for the water temp in the tank to match as closely as possible, the water temperature in the fish's natural habitat. Re-circulating the live well water provides the opportunity to expose the water to chilled pipes or warmed pipes and is frequently the method of varying the temperature of the water.
Thus we have a system in which all three requirements must be a part of any live well for fish. The challenge is finding a way to deliver each of the three requirements in which meeting any one of the requirements has a minimum impact on the other two requirements.
Today, the common method for varying the temperature of the water in the live well is to introduce cooler water from melting ice. While this does indeed lower the water temperature, the amount of ice needed for a full day of fishing on a lake is more than most boats can carry thus fishing boats must return to the docks to replenish ice stores on a regular basis. The round trip from the fishing spot to the docks and back costs a significant amount of money in terms of fishing time lost, gas to transit back and forth and increased boat weight.
The issue of oxygenation of the live well's water is often addressed through the frequency of water circulation. The most common method of oxygenation of the water is to spray the water back into the live well. Spraying has no mechanical parts beyond the circulation pump and is not prone to failure. Spraying does alter the water temperature and depending upon the difference between the ambient air and the desired temperature of the water, additional water cooling may be needed to counter the effects of heat being absorbed by the water from the ambient air. The common method for addressing the rising temperature of the water in the live well is to add ice water to the tank. As described earlier, using ice to cool the water only works when you have ice available.
There are a variety of ways in which these three requirements have been addressed. For example, the use of a radiator through which the water in the live well is passed in order to lower the temperature. While this approach has merit, it relies on filtered water to prevent the clogging of the tiny capillaries located in the radiator. Lake water and organic fish material are likely to bring about such a clogging of the radiator over time. In addition, a radiator is good for cooling but has no ability to heat water should that be necessary.
A similar problem is found when looking at approaches involving a recirculating water system that combines aeration along with cooling to help create a healthful tank environment. This approach also has merit but relies heavily on a tank of ice in order to have cooled coils over which the tank water can pass in order to be cooled. This brings the general problem of ice consumption into the picture thus solving the temperature problem but not addressing the ice problem.
What is needed is a means of addressing all three of the requirements without the use of ice, without mechanical circulation systems that can clog and without having wide swings in water temperature that affect the health of the fish. Such a system ought to be able to be delivered in a variety of forms including being fitted into existing holding tanks in boats, incorporated into new holding tanks in boats and as a stand-alone holding tank that has no reliance on a boat's fittings.